Sound system: Concert Hall on Wheels

Sep 6, 2005
  • World premiere of a new digital technology for perfect listening pleasure
  • First audio system for all recording formats
  • 600-watts amplifiers with signal processors
  • 14 loudspeakers with new metal-matrix technology
The sound system specially developed for the new Mercedes-Benz S-Class offers acoustic excellence equal to that of a live concert experience. In cooperation with the harman/kardon® audio specialists, the Mercedes-Benz sound engineers created a new three-dimensional sound pleasure with a technology deployed for the first time in an automobile. Even in the most critical acoustic environment, in the close quarters of a vehicle cabin, the system ensures a previously inconceivable realistic 360-degree music experience on every seat. No matter whether you enjoy 5.1. or stereo recordings on DVD or CD.
It is a whole bundle of finely tuned technical measures which allow this audible progress. Thus a technological innovation is celebrating its world premier in the automobile: the so-called DTCP technology (Digital Transmission Content Protec-tion). This digital encryption allows the fully digital, content-protected signal transfer via fibre-optic cables from the source to the amplifier. As a result, all signals are transported and processed digitally. This means that during transmission, there is no interference of any kind which could detract from the sound experience.
As this technology avoids the need for a signal conversion from digital into analogue, driver and passengers of the new S-Class may now enjoy for the first time in an automobile the modern multi-channel formats of DVD audio and DVD video as well as DTS-CDs. All multi-channel recordings on DVD and CD such as Dolby-Digital, DTS, MLP and PCM are transferred directly and without loss in quality to the high-performance processor of the amplifier.
An optimum sound impression on all seats is provided by the professional LOGIC7® surround technology from harman/kardon®. It was originally developed for high-performance sound processors in professional recording studios. Now the advanced sound processing method creates an optimum multi-channel audio reproduction in the new S-Class. With special digital algorithms, the LOGIC7® technology achieves a considerably more homogenous sound field than other high-end audio systems. It accurately distributes the surround information as intended in the original recording over the 13-channel system architecture, specifically designed for the S-Class. The perceived sound source is moved away from the individual speakers. This means drivers and passengers enjoy the impression of a larger space with wide sound stage and an authentic surround experience regard-less of seating position.
A concert hall atmosphere on every seat
The LOGIC7® technology even creates a surround sound experience from standard stereo CDs –representing the preponderate share on the music market. Stereo recordings still contain plenty of ambient information from the original master which are with standard CD playback not audible though. The multi-channel surround sound technology LOGIC7® uniquely extracts and recreates this information via all channels of the S-Class system. The system distributes the surround information contained in the two channels over the 13 channels in a way that the sound is distributed markedly more accurate to the loudspeakers and the original recording is considerably more precisely reproduced than in traditional sound systems. Without any artificial effects, you can simply hear what has always been on the stereo CD. The impression is stunning. There is a concert hall atmosphere on each seat in the new S-Class. All the instruments of a piece of music can be accurately located, revealing an impressive and realistic surround sound experience.
Amplifiers with 600 watts performance and digital signal processor
The 600 watts amplifier, located in the rear of the saloon, is responsible for perfect distribution of the music signals. It features a Digital Signal Processor (DSP), which manages the frequency response with calculating capacity equal to that of a PC, ensuring a well-balanced sound impression at any time.
The amplifier generates temperatures of up to 130 degrees during operation. In order to ensure undisturbed operation even under extreme conditions, the Mercedes-Benz and harman/kardon® sound engineers have developed for the new S-Class a particularly complex cooling system with precisely defined heat sinks for the amplifier.
In contrast to the surround system known as DolbyDigital 5.1, the LOGIC7® technology uses a 13-channel system architecture, thus providers an even better and spatially even more convincing audible impression. The S-Class amplifier provides 13 channels to accurately address the loudspeakers. The electronics operates each channel individually, supplying for example 160 watts for the subwoofer and for each woofer channel in the front 80 watts.
Newly developed sandwich-type loudspeaker cones
Signal processing and transmission are not the only decisive factors for sound quality though. As any hi-fi fan knows, loudspeakers are a key factor in the quality of any listening experience. For this reason, new metal matrix loudspeakers were developed for use in the Mercedes-Benz S-Class. Their high-quality membranes are three times stiffer in relation to their weight than traditional loud-speakers. As a result they are highly sensitive.
State-of-the art material engineering is used for manufacturing this sensitive sandwich-type cone body. In a galvanic process, an aluminium substrate is given a ceramic surface. The soft aluminium core provides damping, the ceramic coating layer for strength. Rigidity, damping and low weight – the most important properties of a loudspeaker membrane are thus combined in an ideal fashion. These metal-matrix cones are eminently suitable for deployment in the automobile where they must be able to cope with extraordinarily high loads. They are resistant to moisture, temperature variations and most chemicals.
The new Mercedes-Benz S-Class features 14 of these high-performance loudspeakers. Their computer-modelled metal-matrix radiating surfaces allow virtually no acoustic resonance and discoloration over the entire frequency range. Perfect reproduction of the bass range is generated by a 200 time 320 millimetre oval subwoofer on the rear shelf together with two further 200-millimetre bass speakers in the front doors, each which is flanked by a 100-millimetre mid-range loudspeaker. The high frequencies radiate on the left and right from an additional 43-millimetre tweeter, so forming a fully-fledged three-way system in the front doors.
Further loudspeakers: There is a 100-millimetre mid speaker in the centre of the instrument panel. Left and right in both of the back doors there is one 165-millimeter woofer/mid speaker and a tweeter. And in additional to the powerful subwoofer on the rear shelf two additional mid speakers provide sound to the interior of the new S-Class. The amplifier provides the eleven main channels - centre, front left / right, side left/right, back left/right with 40 watts each, from which the door woofers have alone 80 watts and the subwoofer in the rear shelf has additional 160 watts.
All loudspeakers are integrated into the vehicle structure in an optimum fashion. To do this one of the methods the sound specialists use is to separate the wet area from the interior with an aluminium module in the doors of the new S-Class. The bass loudspeaker operates in the volume of these wet areas, while the mid loudspeakers use the volume between the door module and inner panelling. In this way, there is no interference. The effort is rewarding and audible. In the new S-Class, the middle tones, so decisive for the sound experience sound particularly clean, pure and without distortion.
Sound check with dummy head technology
However, top technical performance alone does not guarantee any extraordinary, benchmark music pleasure in the automobile. Rather, the sound system must be precisely adapted to the vehicle interior. To do this, the Mercedes-Benz and harman/kardon® sound specialists examined the anticipated sound situation in a reproduced vehicle, while the new S-Class was still in the design stage.
When the first prototypes were available, the sophisticated measurement was intensified. By using modern dummy head technology, tests were conducted to examine how various sounds are perceived by people of different sizes across all frequencies on all seats in the vehicle. However, the subjective sensation of sound was even more decisive. With specially selected music recordings, experts with finely attuned ears assessed whether the measured frequency ranges corre-sponded to the subjective sound impression and the spatial sound experience was aligned to the musical model at each seat. Even the most minute of weaknesses were compensated by changing the specifications to the digital signal processor of the amplifier.
Furthermore, the new S-Class sound system had to demonstrate its steadfastness in driving operation on asphalt roads, cobblestones and rough roads. It presented no problems even under extreme temperatures. The system performed as expected, providing a new dimension of sound pleasure in an automobile, even when the vehicle was heated overnight to 50 degrees and the amplifiers worked at full power one hour long generating a volume close to 120 decibels – the equivalent to the sound of a jet taking off from the closest proximity.